Earth's Moon is a small ball of gray rock revolving 239,000 miles around Earth. It is just one of many in the solar system. The Moon has no air and no water. It is about one-fourth as large as Earth.
Moonshine is the Sun's reflection off the Moon. It arrives on Earth in little more than a second after leaving the Moon.
“The Man in the Moon” is the name for the dark shadow of craters and lowlands that appear to those of us in the Northern Hemisphere as a face. In the Southern Hemisphere, however, the Moon appears upside down and appears to people tolook like an old woman with a bundle of twigs.
Full Moon and New Moon describe two phases of the Moon as it orbits Earth. When the Moon is between the Sun and the Earth, its sunlit side is turned away from the Earth and we say there is no Moon. When the Earth is between the Sunand Moon, we can see the entire sunlit side of the Moon and call it a full Moon.
The Far Side of the Moon is always facing away from Earth because of the force of gravity. So when we look at the Moon, we always see the same side.
Moonwalkers: Twelve American astronauts have walked on the Moon. They explored highlands and craters, took photographs, and gathered soil and rocks for study. On July 20, 1969, when the American astronaut Neil Armstrong became the first personto set foot on the Moon, he said, “That's one small step for a man, one giant leap for mankind.”
The moons of Uranus: Uranus has 17 moons. Astronomers detected five of them between 1787 and 1948. The space probe Voyager discovered 10 more in 1985 and 1986. The names of thesemoons are the names of characters from plays by Shakespeare. They are: Oberon, Titania, Umbriel, Ariel, Miranda, Puck, Portia, Juliet, Cressida, Rosalind, Belinda, Desdemona, Cordelia, Ophelia, and Bianca. Miranda, with its deep scars and jumbled surface, isone of the strangest objects in the solar system. It seems to have been shattered by a collision, then pulled back together by gravity! In 1997, two additional moons were discovered, Caliban and Sycorax—also characters from Shakespeare.
The moons of Neptune: Neptune has 8 moons, with Triton the largest. It is covered with a frosty crust, where active volcanoes shoot crystals of nitrogen that look like geysers. The surface temperature of Triton is –390°F, making itthe coldest object in the solar system.
The moon of Pluto: Pluto has 1 moon, Charon. It was discovered in 1978. Because Charon is a relatively large moon—one-fourth the size of Pluto—it is called a “double planet.”
